Cyclohexane-1,3-dione derivatives and their use for controlling undesirable plant growth

ABSTRACT

Cyclohexane-1,3-dione derivatives of the formula ##STR1## where R 1  is C 1  -C 4  -alkyl, R 2  is C 1  -C 5  -alkyl, unsubstituted or halogen-substituted C 2  -C 5  -alkenyl or C 2  -C 5  -alkynyl, R 3  is C 1  -C 10  -alkyl, which contains 2, 3 or 4 of the hetero-atoms O and/or S and/or the groups --SO-- and/or --SO 2  -- in any desired position and R 4  is hydrogen, cyano, methyl or --COOR 5 , where R 5  is C 1  -C 5  -alkyl, and salts of these compounds are used for controlling undesirable plant growth.

The present invention relates to cyclohexane-1,3-dione derivatives,herbicides containing these compounds as active ingredients, and theiruse for controlling undesirable plant growth.

German Laid-Open Application DOS No. 2,822,304 discloses thatcyclohexane-1,3-dione derivatives can be used for selectivelycontrolling undesirable grasses.

We have found that cyclohexane-1,3-dione derivatives of the formula##STR2## where R¹ is C₁ -C₄ -alkyl, R² is C₁ -C₅ -alkyl, unsubstitutedor halogen-substituted C₂ -C₅ -alkenyl or C₂ -C₅ -alkynyl, R³ is C₁ -C₁₀-alkyl, which contains 2, 3 or 4 of the hetero-atoms O and/or S and/orthe groups --SO-- and/or --SO₂ -- in any desired position and R⁴ ishydrogen, cyano, methyl or --COOR⁵, where R⁵ is C₁ -C₅ -alkyl, and saltsof these compounds, have a herbicidal action on grasses and do notdamage broad-leaved crops and monocotyledonous crops which do not belongto the grass family (Gramineae), but on the other hand, surprisingly,are selective in cereal varieties which do belong to the Gramineae.

The compounds of the formula I can occur in several tautomeric forms,all of which are encompassed by the patent claim: ##STR3##

R¹ in formula I is straight-chain or branched C₁ -C₄ -alkyl, such asmethyl, ethyl, n-propyl, i-propyl or n-butyl; R² is straight-chain orbranched C₁ -C₅ -alkyl, unsubstituted or halogen-substituted C₂ -C₅-alkenyl or C₂ -C₅ -alkynyl, such as methyl, ethyl, n-propyl, i-propyl,n-butyl, i-butyl, t-butyl, allyl, 3-chloro-prop-2-enyl,2-chloro-prop-2-enyl, 2,3,3-trichloroprop-2-enyl,2,3-dibromo-prop-2-enyl or propargyl; R³ is straight-chain or branchedC₁ -C₁₀ -alkyl, which contains 2, 3 or 4 of the hetero-atoms O and/or Sand/or the groups --SO-- and/or --SO₂ -- in any desired position, eg.alkoxyalkoxyalkyl, alkylthioalkylthioalkyl, alkylthioalkoxyalkyl,alkoxyalkylthioalkyl, alkylsulfonylalkylsulfonylalkyl,alkoxyalkylsulfonylalkyl or alkoxyalkylalkylsulfinylalkyl, such asethoxyethylthiopropyl, ethylthioethylthiopropyl, ethoxyethylthioethyl,ethylthioethylthioethyl, butoxyethoxyethyl, methoxyethoxyethyl,ethoxyethoxyethyl, 2-ethoxyethylsulfinyl-2-methyl-ethyl or2-ethoxyethylsulfonyl-2-methyl-ethyl.

R⁴ is hydrogen, cyano or methyl, or alkoxycarbonyl of the formula--COOR⁵, where R⁵ is straight-chain or branched C₁ -C₅ -alkyl, such asmethyl, ethyl, i-propyl, n-butyl or n-pentyl.

Compounds of the formula I where R³ is alkylthioalkylthioalkyl oralkoxyalkoxyalkyl, each of 3 to 10, in particular 3 to 6, carbon atoms,and R⁴ is hydrogen are preferred.

Examples of suitable salts of the compounds of the formula I are thealkali metal salts, especially the potassium or sodium salts, alkalineearth metal salts, especially the calcium, magnesium or barium salts,and the manganese, copper, zinc and iron salts.

The compounds of the formula I can be obtained by reacting a compound ofthe formula ##STR4## where R¹, R³ and R⁴ have the above meanings, with ahydroxylamine derivative R² O--NH₃ Y, where R² has the above meaningsand Y is an anion.

The reaction is advantageously carried out in a heterogeneous phasesystem in an inert diluent at from 0° to 80° C. or from 0° C. to theboiling point of the reaction mixture, in the presence of a base, forexample a carbonate, bicarbonate, acetate, alcoholate, hydroxide oroxide of an alkali metal or alkaline earth metal, especially of sodium,potassium, magnesium or calcium. Organic bases, such as pyridine or atertiary amine, can also be used.

The reaction proceeds particularly well in a pH range from 2 to 8,especially from 4.5 to 5.5. The pH range is advantageously establishedby addition of an acetate, eg. an alkali metal acetate, especiallysodium or potassium acetate or a mixture of the two. From 0.5 to 2 molesof alkali metal acetate are added, for example, per mole of ammoniumcompound of the formula R² O--NH₃ Y.

Examples of suitable solvents are dimethylsulfoxide, alcohols, such asmethanol, ethanol and isopropanol, benzene, hydrocarbons orchlorohydrocarbons, such as chloroform, dichloroethane, hexane andcyclohexane, esters, such as ethyl acetate, and ethers, such as dioxaneand tetrahydrofuran.

The reaction is over after a few hours and the reaction product can thenbe isolated by concentration of the mixture, addition of water,extraction with a nonpolar solvent, eg. methylene chloride, anddistillation of the solvent under reduced pressure.

The compounds of the formula I can also be obtained by reacting acompound of the formula II with a hydroxylamine of the formula R²O--NH₂, where R² has the above meanings, in an inert diluent at from 0°C. to 80° C., especially from 15° to 70° C. Where relevant, an aqueoussolution of the hydroxylamine can be used.

Examples of suitable solvents for this reaction are alcohols, such asmethanol, ethanol, isopropanol and cyclohexanol, hydrocarbons orchlorohydrocarbons, such as hexane, cyclohexane, methylene chloride,toluene and dichloroethane, esters, such as ethyl acetate, nitriles,such as acetonitrile, and cyclic ethers, such as tetrahydrofuran.

The compounds of the formula I are also obtained by reacting a compoundof the formula II with hydroxylamine to give the oxime and alkylatingthis oxime with a suitable alkylating agent in accordance with thefollowing equation: ##STR5##

Alkali metal salts of the compounds of the formula I can be obtained bytreating these compounds with sodium hydroxide or potassium hydroxide inaqueous solution or in an organic solvent, eg. methanol, ethanol oracetone. Sodium alcoholates and potassium alcoholates can also be usedas the bases.

The other metal salts, eg. the manganese, copper, zinc, iron, calcium,magnesium and barium salts, can be prepared from the sodium salts byreaction with a corresponding metal chloride in aqueous solution.

The compounds of the formula II can be prepared fromcyclohexane-1,3-diones of the formula III, which can also exist in thetautomeric forms IIIa and IIIb ##STR6## in a conventional manner(Tetrahedron Letters, 29, (1975) (2491).

The derivatives of the formula II can also be prepared by O-acylation ofa cyclohexane-1,3-dione of the formula III with subsequent rearrangementunder acid catalysis (ALCL₃) in accordance with Synthesis (1978) page925, or basic catalysis (pyridine derivatives) in accordance withJapanese Preliminary Published Application No. 79/063,052.

Compounds of the formula III can be obtained from aldehydes of theformula R³ --CH═O in a conventional manner, for example by aldolcondensation with acetone and subsequent cyclization with a malonate asdescribed in Organic Synthesis Coll. Volume II, (1950) page 200.Reaction of an aldehyde of the formula R³ --CHO with malonic acid (Org.Reactions, Volume 15, (1967) page 204), esterification of the resultingacid and cyclization with ethyl acetoacetate also gives a compound ofthe formula III, in a process similar to that described in Chem. Ber. 962946, (1963). The aldehydes of the formula R³ CHO are accessible byadduct formation of a mercaptan with an unsaturated aldehyde (GermanPat. No. 855,704) or by hydroformylation of a corresponding vinyl orallyl ether.

A further possibility for synthesizing the compounds of the formula IIIis the reaction of a γ-halocrotonic acid derivative with a mercaptan oralcohol and cyclization of the resulting γ-mercaptocrotonate orγ-alkoxycrotonate with ethyl acetoacetate as described above.

In the Example which follows and illustrates the preparation of thecyclohexane-1,3-dione derivatives of the formula I, parts by weight bearthe same relation to parts by volume as that of the kilogram to theliter.

EXAMPLE

150 parts by volume of ethanol are dissolved in 12.1 parts by weight of2-butyryl-4-methoxycarbonyl-5-[2-(2-(ethylthio)-ethylthio)-propyl]-cyclohexane-1,3-dione,and 3.3 parts by weight of allyloxyammonium chloride and 2.9 parts byweight of sodium acetate are added. After the mixture has been stirredat room temperature for 20 hours, it is poured into ice-water andextracted with methylene chloride. After stripping off the methylenechloride, 13.0 g of2-(1-allyloxyaminobutylidene)-4-methoxycarbonyl-5-(2-ethylthioethylthio-n-propyl)-cyclohexane-1,3-dioneremain as a yellow oil of n_(D) ²².5 1.5446.

C₂₂ H₃₅ NO₅ S₂ : Molecular weight=458: calculated: C:57.7, H:7.7, N:3.1,S:14.0; found: C:58.0, H:7.5, N:2.9, S:14.0.

The following compounds, for example, were prepared in a similar manner:

    __________________________________________________________________________    Compound                                                                      no.   R.sup.1                                                                           R.sup.2 R.sup.3        R.sup.4                                                                             n.sub.D (Temp. °C.)/NMR-data    __________________________________________________________________________    1     n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 SC.sub.2                              H.sub.5        COOCH.sub.3                                                                         1.5497 (22.5)                          2     n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 SC.sub.2                              H.sub.5        COOCH.sub.3                                                                         1.5446 (22.5)                          3     n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 SC.sub.2                              H.sub.5        H     1.5476 (22.5)                          6     n-C.sub.3 H.sub.7                                                                 CH.sub.2 CCl═CCl.sub.2                                                            CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 SC.sub.2                              H.sub.5        H     1.5638 (22.5)                          10    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 OC.sub.2                              H.sub.5        H     1.5252 (20.5)                          11    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 OC.sub.2                              H.sub.5        H     1.5300 (22)                            16    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 O--n-C.sub.4                             H.sub.9        H     1.4922 (23)                            17    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 O--n-C.sub.4                             H.sub.9        H     1.4984 (23)                            19    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 OCH.sub.3                                               H     1.5006 (22)                            20    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 OCH.sub.3                                               H     1.5078 (22)                            21    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CHCl                                                                  CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 OCH.sub.3                                               H     1.5192 (21)                            22    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH(CH.sub.3)OCH.sub.2 CH.sub.2 O--n-C.sub.4 H.sub.9                                          H     1.4895 (24)                            23    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH(CH.sub.3)OCH.sub.2 CH.sub.2 O--n-C.sub.4 H.sub.9                                          H     1.4956 (24)                            27    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.3 OCH.sub.3                                             H     1.4979 (22)                            28    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.3 OCH.sub.3                                             H     1.4976 (22)                            29    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CHCl                                                                  CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.3 OCH.sub.3                                             H     1.5065 (22)                            34    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.2 OCH.sub.3                                             H     1.4951 (22)                            35    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.2 OCH.sub.3                                             H     1.5009 (22)                            44    n-C.sub.3 H.sub.7                                                                 n-C.sub.3 H.sub.7                                                                     CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 OCH.sub.3                                               H     1.5003 (21)                            45    n-C.sub.3 H.sub.7                                                                 CH.sub.2 --C.tbd.CH                                                                   CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 OCH.sub.3                                               H     δ = 3.40 ppm (OCH.sub.3)                                                δ = 2.50 ppm                     __________________________________________________________________________                                           (.tbd.CH)                          

The following compounds may for example be prepared analogously:

    __________________________________________________________________________    Compound                                                                      no.   R.sup.1                                                                           R.sup.2 R.sup.3           R.sup.4                                   __________________________________________________________________________    4     n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 SC.sub.2                              H.sub.5           H                                         5     n-C.sub.3 H.sub.7                                                                 CH.sub.2 CCl═CH.sub.2                                                             CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 SC.sub.2                              H.sub.5           H                                         7     n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CHCl                                                                  CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 SC.sub.2                              H.sub.5           H                                         8     n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH.sub.2 CH(CH.sub. 3)SO.sub.2 CH.sub.2 CH.sub.2                              SO.sub.2 C.sub.2 H.sub.5                                                                        H                                         9     n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 OC.sub.2                              H.sub.5           COOCH.sub.3                               12    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CHCl                                                                  CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 OC.sub.2                              H.sub.5           H                                         13    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CCl═CHCl                                                                 CH.sub.2 CH(CH.sub.3)SCH.sub.2 CH.sub.2 OC.sub.2                              H.sub.5           H                                         14    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH.sub.2 CH(CH.sub. 3)SOCH.sub.2 CH.sub.2 OC.sub.2                            H.sub.5           H                                         15    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH.sub.2 CH(CH.sub.3)SO.sub.2 CH.sub.2 CH.sub.2                               OC.sub.2 H.sub.5  H                                         18    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CHCl                                                                  CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 O--n-C.sub.4                             H.sub.9           H                                         24    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CHCl                                                                  CH(CH.sub.3)OCH.sub.2 CH.sub.2 O--n-C.sub.4 H.sub.9                                             H                                         25    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.3 OCH.sub.3                                                COOCH.sub.3                               26    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.3 OCH.sub.3                                                COOCH.sub.3                               30    C.sub.2 H.sub.5                                                                   C.sub.2 H.sub.5                                                                       CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.3 OCH.sub.3                                                H                                         31    C.sub.2 H.sub.5                                                                   CH.sub.2 CH═CH.sub.2                                                              CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.3 OCH.sub.3                                                H                                         32    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.2 OCH.sub.3                                                COOCH.sub.3                               33    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.                                                           COOCH.sub.3                               36    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CHCl                                                                  CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.2 OCH.sub.3                                                H                                         37    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CCl═CH.sub.2                                                             CH(CH.sub.3)(OCH.sub.2 CH.sub.2).sub.2 OCH.sub.3                                                H                                         38    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 SC.sub.2 H.sub.5                                           H                                         39    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 SC.sub.2 H.sub.5                                           H                                         40    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH(CH.sub.3)OCH.sub.2 CH.sub.2 SC.sub.2 H.sub.5                                                 H                                         41    n-C.sub.3 H.sub.7                                                                 CH.sub.2 CH═CH.sub.2                                                              CH(CH.sub.3)OCH.sub.2 CH.sub.2 SC.sub.2 H.sub.5                                                 H                                         42    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.7                                                                       CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 OCH.sub.3                                                  CN                                        43    n-C.sub.3 H.sub.7                                                                 C.sub.2 H.sub.5                                                                       CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 OCH.sub.3                                                  CH.sub.3                                  __________________________________________________________________________

The compounds of the formula I may be applied for instance in the formof directly sprayable solutions, powders, suspensions (includinghigh-percentage aqueous, oily or other suspensions), dispersions,emulsions, oil dispersions, pastes, dusts, broadcasting agents, orgranules by spraying, atomizing, dusting, broadcasting or watering. Theforms of application depend entirely on the purpose for which the agentsare being used, but they must ensure as fine a distribution of theactive ingredient according to the invention as possible.

For the preparation of solutions, emulsions, pastes and oil dispersionsto be sprayed direct, mineral oil fractions of medium to high boilingpoint, such as kerosene or diesel oil, further coal-tar oils, and oilsof vegetable or animal origin, aliphatic, cyclic and aromatichydrocarbons such as benzene, toluene, xylene, paraffin,tetrahydronaphthalene, alkylated naphthalenes and their derivatives suchas methanol, ethanol, propanol, butanol, chloroform, carbontetrachloride, cyclohexanol, cyclohexanone, chlorobenzene, isophorone,etc., and strongly polar solvents such as dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, water, etc. are suitable.

Aqueous formulations may be prepared from emulsion concentrates, pastes,oil dispersions or wettable powders by adding water. To prepareemulsions, pastes and oil dispersions the ingredients as such ordissolved in an oil or solvent may be homogenized in water by means ofwetting or dispersing agents, adherents or emulsifiers. Concentrateswhich are suitable for dilution with water may be prepared from activeingredient, wetting agent, adherent, emulsifying or dispersing agent andpossibly solvent or oil.

Examples of surfactants are: alkali metal, alkaline earth metal andammonium salts of ligninsulfonic acid, naphthalenesulfonic acids,phenolsulfonic acids, alkylaryl sulfonates, alkyl sulfates, and alkylsulfonates, alkali metal and alkaline earth metal salts ofdibutylnaphthalenesulfonic acid, lauryl ether sulfate, fatty alcoholsulfates, alkali metal and alkaline earth metal salts of fatty acids,salts of sulfated hexadecanols, heptadecanols, and octadecanols, saltsof sulfated fatty alcohol glycol ethers, condensation products ofsulfonated naphthalene and naphthalene derivatives with formaldehyde,condensation products of naphthalene or naphthalenesulfonic acids withphenol and formaldehyde, polyoxyethylene octylphenol ethers, ethoxylatedisooctylphenol, ethoxylated octylphenol and ethoxylated nonylphenol,alkylphenol polyglycol ethers, tributylphenyl polyglycol ethers,alkylaryl polyether alcohols, isotridecyl alcohol, fatty alcoholethylene oxide condensates, ethoxylated castor oil, polyoxyethylenealkyl ethers, ethoxylated polyoxypropylene, lauryl alcohol polyglycolether acetal, sorbitol esters, lignin, sulfite waste liquors and methylcellulose.

Powders, dusts and broadcasting agents may be prepared by mixing orgrinding the active ingredients with a solid carrier.

Granules, e.g., coated, impregnated or homogeneous granules, may beprepared by bonding the active ingredients to solid carriers. Examplesof solid carriers are mineral earths such as silicic acid, silica gels,silicates, talc, kaolin, Attaclay, limestone, lime, chalk, bole, loess,clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate,magnesium oxide, ground plastics, fertilizers such as ammonium sulfate,ammonium phosphate, ammonium nitrate, and ureas, and vegetable productssuch as grain flours, bark meal, wood meal, and nutshell meal,cellulosic powders, etc.

The formulations contain from 0.1 to 95, and preferably 0.5 to 90, % byweight of active ingredient.

Examples of formulations are given below.

I. 90 parts by weight of compound no. 16 is mixed with 10 parts byweight of N-methyl-alpha-pyrrolidone. A mixture is obtained which issuitable for application in the form of very fine drops.

II. 10 parts by weight of compound no. 17 is dissolved in a mixtureconsisting of 90 parts by weight of xylene, 6 parts by weight of theadduct of 8 to 10 moles of ethylene oxide and 1 mole of oleicacid-N-monoethanolamide, 2 parts by weight of the calcium salt ofdodecylbenzenesulfonic acid, and 2 parts by weight of the adduct of 40moles of ethylene oxide and 1 mole of castor oil.

III. 20 parts by weight of compound no. 20 is dissolved in a mixtureconsisting of 60 parts by weight of cyclohexanone, 30 parts by weight ofisobutanol, 5 parts by weight of the adduct of 7 moles of ethylene oxideand 1 mole of isooctylphenol, and 5 parts by weight of the adduct of 40moles of ethylene oxide and 1 mole of castor oil.

IV. 20 parts by weight of compound no. 19 is dissolved in a mixtureconsisting of 25 parts by weight of cyclohexanol, 65 parts by weight ofa mineral oil fraction having a boiling point between 210° and 280° C.,and 10 parts by weight of the adduct of 40 moles of ethylene oxide and 1mole of castor oil. By pouring the solution into 100,000 parts by weightof water and uniformly distributing it therein, an aqueous dispersion isobtained containing 0.02% by weight of the active ingredient.

V. 80 parts by weight of compound no. 22 is well mixed with 3 parts byweight of the sodium salt of diisobutylnaphthalene-alpha-sulfonic acid,10 parts by weight of the sodium salt of a lignin-sulfonic acid obtainedfrom a sulfite waste liquor, and 7 parts by weight of powdered silicagel, and triturated in a hammer mill.

VI. 5 parts by weight of compound no. 3 is intimately mixed with 95parts by weight of particulate kaolin. A dust is obtained containing 5%by weight of the active ingredient.

VII. 30 parts by weight of compound no. 1 is intimately mixed with amixture consisting of 92 parts by weight of powdered silica gel and 8parts by weight of paraffin oil which has been sprayed onto the surfaceof this silica gel. A formulation of the active ingredient is obtainedhaving good adherence.

VIII. 20 parts of compound no. 3 is intimately mixed with 2 parts of thecalcium salt of dodecylbenzenesulfonic acid, 8 parts of a fatty alcoholpolyglycol ether, 2 parts of the sodium salt of a phenolsulfonicacid-urea-formaldehyde condensate and 68 parts of a paraffinic mineraloil. A stable oily dispersion is obtained.

The agents may be applied pre- or postemergence. Preferably, the novelactive ingredients, or agents containing them, are applied afteremergence of the unwanted plants. If certain crop plants tolerate theactive ingredients less well, application techniques may be used inwhich the herbicidal agents are sprayed from suitable equipment in sucha manner that the leaves of sensitive crop plants are if possible nottouched, and the agents reach the soil or the unwanted plants growingbeneath the crop plants (post-directed, lay-by treatment).

The amount of active ingredient applied depends on the time of the year,the plants to be combated, and the growth stage of the plants, andvaries from 0.025 to 5 kg/ha and more, but is preferably from 0.125 to 3kg/ha.

The influence of cyclohexane-1,3-dione derivatives of the formula I onthe growth of grasses (Gramineae) and broadleaved crop plants isdemonstrated in greenhouse experiments.

The vessels employed were plastic flowerpots having a volume of 300 cm³,and which were filled with a sandy loam containing about 1.5% humus. Theseeds of the test plants were sown shallow, and separately, according tospecies. For the preemergence treatment, the active ingredients wereapplied to the surface of the soil immediately after the seeds had beensown. The compounds were emulsified or suspended in water as vehicle,and sprayed through finely distributing nozzles. The application ratewas 3.0 kg of active ingredient per hectare. After the agents had beenapplied, the vessels were lightly sprinkler-irrigated to inducegermination and growth and to activate the chemical agents. Transparentplastic covers were then placed on the vessels until the plants hadtaken root. The cover ensured uniform germination of the plants, insofaras this was not impaired by the active ingredients.

For the postemergence treatment, the plants were first grown in thevessels to a height of from 3 to 15 cm, depending on growth form, beforebeing treated. The soybean plants used for the postemergence treatmentwere grown in a peat-enriched substrate to ensure better growth than ispossible in a sandy loam. For this treatment, either plants which hadbeen sown directly in the pots and grown there were selected, or plantswhich had been grown separately as seedlings and transplanted to theexperiment vessels a few days before treatment. No covers were placed onthe pots in this treatment method. The application rates forpostemergence treatment varied from ingredient to ingredient, and wereeither 0.125 or 0.25 kg of active ingredient per hectare.

The pots were set up in the greenhouse-species from warmer areas at from20° to 35° C., and species from moderate climates at 10° to 20° C. Theexperiments were run for 2 to 4 weeks. During this period, the plantswere tended and their reactions to the various treatments assessed. Thescale used for assessment was 0 to 100, 0 denoting no damage or normalemergence, and 100 denoting nonemergence or complete destruction of atleast the visible plant parts.

The following test plants were used in the experiments:

Alopecurus myosuroides (slender foxtail)

Beta vulgaris (sugarbeets)

Brassica napus (rapeseed)

Bromus tectorum (downy brome)

Digitaria sanguinalis (large crabgrass)

Echinochloa crus-galli (barnyardgrass)

Glycine max. (soybeans)

Lolium multiflorum (Italian ryegrass)

Setaria italica (foxtail)

Triticum aestivum (wheat).

The agent used for comparison purposes was2-(1-ethoxyaminobutylidene)-5-(2-ethylthiopropyl)-cyclohexane-1,3-dione(German Laid-Open Application DE-OS No. 2,822,304)-A.

On preemergence application, for example compound nos. 1, 3, 16, 17, 19and 20 had a marked herbicidal action on grassy species.

On postemergence application, for example compound no. 22, applied atrates of 0.125 and 0.25 kg/ha, combated unwanted plant species, and wasfully tolerated by broadleaved crop plants and impaired wheat onlyslightly. By contrast, prior art comparative agent A caused very heavydamage to wheat. Compound no. 3, on postemergence application, had abetter action on Bromus tectorum than comparative agent A.

In view of the good tolerance of the compounds according to theinvention and the numerous application methods possible, they may beused in a further large number of crops for removing unwanted grasses,or grassy crop plants growing where they are not required.

The following crops may be mentioned by way of example:

    ______________________________________                                        Botanical name       Common name                                              ______________________________________                                        Allium cepa          onions                                                   Ananas comosus       pineapples                                               Arachis hypogaea     peanuts (groundnuts)                                     Asparagus officinalis                                                                              asparagus                                                Beta vulgaris spp. altissima                                                                       sugarbeets                                               Beta vulgaris spp. rapa                                                                            fodder beets                                             Beta vulgaris spp. esculenta                                                                       table beets, red beets                                   Brassica napus var. napus                                                                          rape                                                     Brassica napus var. napobrassica                                              Brassica napus var. rapa                                                                           turnips                                                  Brassica rapa var. silvestris                                                 Camellia sinensis    tea plants                                               Carthamus tinctorius safflower                                                Carya illinoinensis  pecan trees                                              Citrus limon         lemons                                                   Citrus maxima        grapefruits                                              Citrus reticulata    mandarins                                                Citrus sinensis      orange trees                                             Coffea arabica (Coffea canephora,                                                                  coffee plants                                            Coffea liberica)                                                              Cucumis melo         melons                                                   Cucumis sativus      cucumbers                                                Daucus carota        carrots                                                  Elais guineensis     oil palms                                                Fragaria vesca       strawberries                                             Glycine max          soybeans                                                 Gossypium hirsutum   cotton                                                   (Gossypium arboreum                                                           Gossypium herbaceum                                                           Gossypium vitifolium)                                                         Helianthus annuus    sunflowers                                               Helianthus tuberosus                                                          Hevea brasiliensis   rubber plants                                            Hordeum vulgare      barley                                                   Humulus lupulus      hops                                                     Ipomoea batatas      sweet potatoes                                           Juglans regia        walnut trees                                              Lactuca sativa      lettuce                                                  Lens culinaris       lentils                                                  Linum usitatissimum  flax                                                     Lycopersicon lycopersicum                                                                          tomatoes                                                 Malus spp.           apple trees                                              Manihot esculenta    cassava                                                  Medicago sativa      alfalfa (lucerne)                                        Mentha piperita      peppermint                                               Musa spp.            banana plants                                            Nicothiana tabacum   tobacco                                                  (N. rustica)                                                                  Olea europaea        olive trees                                              Phaseolus lunatus    limabeans                                                Phaseolus mungo      mungbeans                                                Phaseolus vulgaris   snapbeans, green beans,                                                       dry beans                                                Petroselinum crispum parsley                                                  spp. tuberosum                                                                Picea abies          Norway spruce                                            Abies alba           fir trees                                                Pinus spp.           pine trees                                               Pisum sativum        English peas                                             Prunus avium         cherry trees                                             Prunus domestica     plum trees                                               Prunus dulcis        almond trees                                             Prunus persica       peach trees                                              Pyrus communis       pear trees                                               Ribes sylvestre      redcurrants                                              Ribes uva-crispa     gooseberries                                             Ricinus communis     castor-oil plants                                        Saccharum officinarum                                                                              sugar cane                                               Secale cereale       rye                                                      Sesamum indicum      sesame                                                   Solanum tuberosum    Irish potatoes                                           Spinacia oleracea    spinach                                                  Theobroma cacao      cacao plants                                             Trifolium pratense   red clover                                               Triticum aestivum    wheat                                                    Vaccinium corymbosum blueberries                                              Vaccinium vitis-idaea                                                                              cranberries                                              Vicia faba           tick beans                                               Vigna sinensis (V. unguiculata)                                                                    cow peas                                                 Vitis vinifera       grapes                                                   ______________________________________                                    

To increase the spectrum of action and to achieve synergistic effects,the cyclohexane-1,3-dione derivatives of the formula I may be mixed andapplied together with numerous representatives of other herbicidal orgrowth-regulating active ingredient groups. Examples of suitable mixturecomponents are diazines, 4H-3,1-benzoxazine derivatives,benzothiadiazinones, 2,6-dinitroanilines, N-phenyl-carbamates,thiolcarbamates, halocarboxylic acids, triazines, amides, ureas,diphenyl ethers, triazinones, uracils, benzofuran derivatives, etc.

It may also be useful to apply the novel compounds, either on their ownor combined with other herbicides, in admixture with other cropprotection agents, e.g., agents for combating pests or phytopathogenicfungi or bacteria. The compounds may also be mixed with solutions ofmineral salts used to remedy nutritional or trace element deficiencies.Non-phytotoxic oils and oil concentrates may also be added.

We claim:
 1. A cyclohexane-1,3-dione derivative of the formula ##STR7##where R¹ is C₁ -C₄ -alkyl, R² is C₁ -C₅ -alkyl, unsubstituted orhalogen-substituted C₂ -C₅ -alkenyl or C₂ -C₅ -alkynyl, R³ is C₁ -C₁₀-alkyl, which contains 2, 3 or 4 of the hetero-atoms O and/or S and/orthe groups --SO-- and/or --SO₂ -- in any desired position and R⁴ ishydrogen, cyano, methyl or --COOR⁵, where R⁵ is C₁ -C₅ -alkyl, or a saltthereof.
 2. A cyclohexane-1,3-dione of the formula I as claimed in claim1, where R³ is alkylthioalkylthioalkyl or alkoxyalkoxyalkyl of 3 to 10carbon atoms and R⁴ is hydrogen. 3.2-(1-Ethoxyaminobutylidene)-5-(2-ethylthioethylthio-n-propyl)-cyclohexane-1,3-dione.4. A herbidical composition for use on unwanted grasses which comprises:inert additives and from 0.1 to 95 wt% of a cyclohexane-1,3-dionederivative of the formula I or a salt of such a cyclohexane-1,3-dionederivative as claimed in claim
 1. 5. A herbicidal composition as definedin claim 4, where R³ of the compound of the formula I isalkylthioalkylthioalkyl or alkoxyalkoxyalkyl of 3 to 10 carbon atoms andR⁴ is hydrogen, or a salt of such a cyclohexane-1,3-dione derivative. 6.A herbicidal composition for use on unwanted grasses comprising: inertadditives and from 0.1 to 95 wt% of 2-(1-ethoxyethoxyaminobutylidene)-5-(2-ethylthioethylthio-n-propyl)-cylclohexane-1,3-dione.7. A process for combating the growth of unwanted grasses, wherein theunwanted grasses and/or the area to be kept free from the unwantedgrasses are treated with a herbicidally effective amount of acyclohexane-1,3-dione derivative of the formula I as claimed in claim 1,or a salt of a cyclohexane-1,3-dione derivative of the formula I asclaimed in claim 1.